The invention relates generally to gas treatment systems, and more particularly to a system and a method for treatment of a post combustion flue gas.
In combustion-based systems such as a power plant, for example, a flue gas is produced when coal or other types of fuel are burned in air. The heat released by combustion generates steam, which drives a turbine generator for producing electric power. Hot combustion gases exiting the boiler include nitrogen and smaller concentrations of water vapor and carbon dioxide. Other constituents, formed from impurities in coal, include sulfur dioxide, nitrogen oxides, and particulate matter (fly ash). Such pollutants must be removed to meet environmental standards.
One effective method to remove carbon dioxide from the flue gas is by chemical reaction with a liquid solvent because the flue gas is at atmospheric pressure and the concentration of carbon dioxide is low (typically around 12-15% by volume for coal plants, for example). The most commonly used solvents are a family of organic amines, a subclass for example, are amino silicones. The flue gas is “scrubbed” with an amine solution, inside a vessel referred to as an absorber, typically capturing a higher percentage of the carbon dioxide. The carbon dioxide-laden solvent is then pumped to another vessel, referred to as a regenerator, where heat releases the carbon dioxide as a gas. The resulting concentrated carbon dioxide gas stream is then compressed into a supercritical fluid for transport and the solvent is recycled.
Amino silicone, for example, is an expensive solvent. The drawbacks associated with conventional treatment systems are that there is a substantial loss of the amino silicone solvent along with the clean flue gas exiting the absorber.
There is a need for an enhanced system and method for treatment of flue gas to reduce a solvent loss.